In 1964, filmmaker Henri-Georges Cluzot -- the French master behind such films as "Les Diaboliques" and "The Wages of Fear" -- set out to make his most ambitious film yet.

French director Henri-Georges Clouzot and actress Romy Schneider, on the set of the unfinished thriller 'Inferno.'

"Inferno" was a story of obsession, of passion, of one tragic figure's eventual undoing. It was never completed.

Now, nearly a half-century later, documentary filmmakers Serge Bromberg and Ruxandra Medrea Annonier set out to tell the story Clouzot could not. It, too, is a story of obsession, of passion and of one tragic figure's undoing. In this case, however, that figure happens to be Clouzot himself.

Their film, "Henri-George Clouzot's Inferno, " is a fascinating peek behind the scenes of Clouzot's colossal failure, a singular making-of documentary that recounts exactly what went wrong -- but one that also paints a compelling portrait of what happens when an artist's ego is allowed to run amok.

As "Inferno" tells us, Clouzot -- known by some as "the French Hitchcock" -- was given an unlimited budget by Columbia Pictures to make his film. And that's where the troubles started. With all that money, Clouzot was able to indulge a vision that had the potential to revolutionize cinema.

He started out by launching an extensive ---- and expensive -- pre-production period in which he experimented with various optical effects intended to illustrate the onset of madness in his main character.

Actress Romy Schneider, in an image from Henri-Georges Clouzot's 'Inferno.'

It ate up time, it ate up money -- but everyone believed Clouzot was creating something truly special, so he was given the room he needed to create. Bad move.

When shooting finally began, things only worsened. The bulk of his enormous crew often found themselves standing around while he obsessed over the details of a single shot. The famously demanding director also brought out the worst in his lead actor, who walked off the set. Clouzot's own health would come into play as well.

Three weeks into principal photography, the film would be shut down. The result: 15 hours of footage on 185 cans of film, stashed away and largely forgotten.

Then decades later, Bromberg found himself trapped in a malfunctioning elevator with a woman who turned out to be Clouzot's second wife. He talked her into giving him access to the "Inferno" footage, and set about making his documentary.

Combining that original footage with interviews of key "Inferno" production figures, as well as the restaging of key scenes, Bromberg and Annonier cobble together an approximation of Clouzot's narrative.

What they end up with is a movie that, one suspects, comes close to capturing the emotion and descent into madness the late director had originally intended -- although not at all how he had planned on doing so.